Large volumes of printed matter are usually produced by a process such as offset printing. In offset printing, plates are produced for each page and the high initial cost associated with the production of plates is recovered by the large volume of pages produced from each plate. However, for low volume production, offset printing is expensive. Publications such as tax guides, patent examining guides, and many other similar publications, often using ring binders, may have relatively small portions of the whole publication updated and changed on a rather frequent basis. In such cases, offset printing of the updated material may not be economical. For low volume printing, computerized print-on-demand systems, frequently utilizing electrophotographic technology, are considerably cheaper than offset printing.
Another cost factor in the publishing industry is the labor intensive nature of the operation, that is, when a document is produced, sometimes comprising several hundred pages, the plates that produced those pages may be stored so that if the document is later out of print, the plates can be retrieved to produce a new edition. In addition to storing plates, after printing the publication the pages must also be stored in a warehouse so that subsequent orders can be satisfied. Retrieving documents from a warehouse is labor intensive, particularly where the document includes frequent revisions. Those revisions must also be printed, stored and retrieved to satisfy customer requirements which may include the latest version, an earlier version, only the changed pages of the latest version, or a sub-portion of a current or old version. After many iterations of this procedure, the result is several versions and changed pages all of which are stored in a warehouse. When a customer request is received, it requires locating the correct pages in the warehouse and assembling them to meet the order. The process is not only labor intensive, it is subject to human error. For insurance companies, assembling a policy often requires printing different versions of the same clause for different jurisdictions. Over a period of time, storage of policies and variations of them fill large warehouses. Print-on-demand systems avoid the warehousing of documents but fail to provide a convenient management system for the retrieval and printing of a particular version or part thereof.
The solution to these problems is to create and maintain a document database, using the power and flexibility of the database to manage the production of documents to satisfy customer needs. In such manner, the document version or portion thereof can be retrieved at a later point in time for printing by the most economical process, either offset printing or print-on-demand. In providing such a database, document records, version records, and page records for each page are created and maintained. These records are searched in the database to identify a list of pages needed to satisfy a customer request.
One of the most common languages and datastreams for producing documents to be printed has been "PostScript." However, PostScript, as well as many other source languages, fails to provide a vehicle for creating and maintaining the records needed for a management system to retrieve the required pages to meet a print request for a customer. This invention provides a solution to the problem by utilizing the comment field of the PostScript page files to enable the editor or author to provide document management data. PostScript comment fields are ordinarily ignored by PostScript interpreters in the preparation of page image files for printing since only the contents of the page are printed, not comments. Therefore, prior art interpreters do not provide a vehicle for the processing of management information located in comment fields. The object of this invention is to provide a marking technique to identify those portions of the comment field of PostScript page files which contain document management information and to provide special processing capability to identify those marks and create page characteristic records for storage in a database. The document management data will continue to be ignored in the preparation of a page image file.